DE69130549T2 - Device for generating an object movement path - Google Patents

Description

The present invention relates to a device for generating a movement path of an object.

In a three-dimensional computer graphics system as described in "Practical Computer Graphics, Fundamental Procedures and Applications", Nikkan Kogyo Shinbun Co. Ltd., page 390, in order to realize the substantial quality of the image of an object, it is necessary to adjust the colors of ambient light components, scattered light components and specular light components. A method for adjusting motion of moving images is discussed in "ASCII Learning System (3), Application Course, Applied Graphics", Otha et al. (1986), pages 105 to 126. According to this method, a key frame is generated every second, in each key frame the position of an object is determined, and intermediate images are generated by interpolation using linear spline curves or higher order spline curves. Japanese patent application JP-A-2-199579 is also known, according to which, after inputting a movement location, movement speeds at positions at the location are input independently at predetermined time intervals.

The conventional techniques described above require a large amount of information to be input in order to produce moving images. This represents a significant obstacle to creating a system that can be easily used by everyone.

For example, many parameters are required to determine a surface reflectance attribute. Considerable skill and expertise are required to set appropriate values for these parameters.

Furthermore, to define the motion of a moving image, it is necessary to determine both the position and the viewing direction or angle of an object using a key frame. It is therefore necessary for the operator to determine the position of an object, while also taking into account the speed and viewing direction of the object.

In the paper "SAM-Animation Software for Simulating Articulated Motion" by Maciejewski and Klein in "Computer and Graphics", Volume 9, No. 4, 1985, pages 383 - 391, a simulation of joint movements is disclosed. The process begins with a definition of an object with joints and defines movements using matrices.

It is the object of the present invention to define movements in such a way that they can be coupled with one another evenly.

It is a further object of the present invention to determine the path and/or surface reflection attributes of an object with a small number of procedures.

It is a further object of the invention to provide a device for dynamically varying either the position of an object, the magnitude and direction of the velocity of an object and the time to enable easy definition.

These objects are achieved according to the features of patent claim 1. The dependent claims relate to preferred embodiments of the invention.

To simplify the determination of the position of an object and the magnitude and direction of the velocity of a Object, the position of an object is displayed as the starting point of a vector representation, and the magnitude and direction of the velocity of an object are displayed as the length and orientation of the vector. An input device is provided for dynamically changing the vector representation.

To more precisely determine a given motion path of an object, a new key frame is created by generating a new speed at a freely selectable point on the path.

A device is provided which independently defines a specific color of an object and its surface reflection attribute to determine the surface attribute of the object. For example, information concerning specific colors and surface reflection attributes of objects is stored in a database so that a desired quality of the image of a material can be realized by a combination of a specific color and a surface reflection attribute.

To define the movement of a moving image, a device is provided which separates the movement of an object into the position of the object at a certain time and its viewing direction in order to thereby define the movement of the object independently.

To adjust the position of an object, either the position and the velocity of an object, or one or both, are used at each key frame, allowing a computer to automatically generate a motion path between key frames.

Similarly, to adjust the direction of view of an object, either the direction of view of an object and its angular velocity, or one of both, are used at each key frame, so that a computer can automatically ically generate the viewing direction of the object between the key frames. In particular, for example, a certain restriction is provided for controlling the viewing direction of an object in order to enable easy setting, such as a setting for an image display in which a camera always captures an object in the center of a frame.

A device for generating the motion path may comprise:

an input device for inputting information representing the position of a starting point of the movement of an object, information representing at least one of the magnitude and the direction of the speed at the starting point of the movement of the object, information representing an end point of the movement of the object, and information representing at least one of the magnitude and the direction of a speed at the end point of the movement of the object; and

means for calculating information representing a movement path from the starting point to the end point of the movement of the object according to the information representing the position of a starting point of the movement of an object, the information representing at least one of the magnitude and the direction of the speed at the starting point of the movement of the object, the information representing an end point of the movement of the object, and the information representing at least one of the magnitude and the direction of a speed at the end point of the movement of the object.

A device for generating the motion path of an object may comprise:

an input device for entering information representing the position of a moving object and the Information representing the viewing direction of the moving object; and

a device for calculating information representing the movement path of the moving object according to the information representing the position of the moving object and the information representing the viewing direction of the moving object.

Another device for generating the movement path of an object may comprise:

means for displaying information on a display screen, the information representing the position of a moving object;

means for displaying a symbol on the display, wherein the symbol represents the time corresponding to the position of the moving object;

means for calculating information representing the movement path of the moving object according to the information input by means of the symbol representing the time corresponding to the position of the moving object and the information representing at least one of the magnitude and the direction of a speed of the moving object at the position; and

means for displaying information on the display screen, the information representing the path of motion of the moving object.

The further objects and advantages of the present invention will become apparent from the following description of the embodiments.

Fig. 1 illustrates an example of an operation according to an embodiment of the present invention;

Fig. 2 shows the system arrangement according to the embodiment of the present invention;

Fig. 3 shows a display example of path data;

Fig. 4 is a diagram showing the structure of a key frame data management;

Figs. 5a to 5c are diagrams showing a display example of a procedure for changing a path;

Fig. 6 is a diagram showing an example of an application to a presentation system;

Figures 7 to 29 show further embodiments of the present invention;

Fig. 30 shows the structure of the main part of a computer graphics system according to an embodiment of the present invention;

Fig. 31 shows the detailed structure of the device for adjusting the surface reflection attribute according to Fig. 30;

Fig. 32 shows a sphere illuminated by a light source;

Fig. 33 shows an HLS color model;

Fig. 34 illustrates a user interface;

Fig. 35 illustrates the effects of an ambient light slider and a scattered light slider;

Fig. 36 illustrates the effects of a slider for the image quality of metal and a slider for specular light; and

Fig. 37 illustrates a user interface according to another embodiment.

An embodiment of the present invention will be described with reference to the accompanying drawings, which illustrate, by way of example, three-dimensional animated computer graphics.

Fig. 1 illustrates an environment for defining moving images according to the present invention. Using a mouse 103 as a pointing device and a keyboard 104 or the like serving as an input device, the operator designates a movement path or course of an object displayed on a screen 101 of a display such as a liquid crystal display (LCD) and then realizes the moving images upon operation of a control panel 105.

Fig. 2 shows the structure of the system. An event determined by the operator using the input devices such as the mouse 103 is interpreted by an input processing device 201 which, if the event is an actuation of the object, issues an instruction to an object management unit 202 and, if the event is an instruction to change a movement, to a movement management unit 203.

The object management unit 202 manages the creation and modification of shape data of an object to be moved as a moving image and stores the shape data in an object data storage unit 204. The motion management unit 203 manages the creation and modification of the motion of an object and stores data for defining motions in a motion data storage unit 205. Path data for motions is also stored in the motion data storage unit 205.

If the operator gives the instruction to realize a moving image of an object on the screen 101 by operating the control panel 105, the generated shape data of the object and the movement data are processed by a unit 206 to execute a trick sequence, which in turn converts the read data into a chain of graphics functions and instructs a graphics driver 207 to display them. Moving images are then displayed on the display screen 101.

The procedure for setting the path by the movement management unit 203 will be described, which is the main part of the present embodiment.

The motion management unit 203 performs the following processing when path assignment is made using a velocity vector. First, the timings that define a motion are input via the control panel 105. The input timings are stored as the timings corresponding to the respective key frames. The timing at the start point of a key frame for the start point is represented by T0, and the timing at the end point of a key frame for the end point is represented by Tn. Next, the positions of the start and end points are determined. The determined positions are represented by the three-dimensional coordinates (X0, Y0, Z0) and (Xn, Yn, Zn).

Then the velocities are calculated. The velocities are calculated as shown below in such a way that they produce a uniform motion from the starting point to the end point.

Vx = (Xn - X0)/(Tn - T0)

Vy = (Yn - Y0)/(Tn - T0)

Vz = (Zn - Z0)/(Tn - T0)

The velocity vectors are displayed using the calculated velocity components. The velocity vectors are displayed near the start and end points of the location. The velocity vector at the start point is

for the coordinates of the starting point of a vector by (X0, Y0, Z0) and

for the coordinates of the end point of a vector by (X0 + K · Vx, Y0 + K · Vy, Z0 + K · Vz)

K is a coefficient used to make the vector representation easily recognizable.

The vector at the endpoint is obtained in a similar way.

If the path is to be changed or corrected, the following procedure is carried out. First, the path or velocity vector to be changed is determined using an input device 103, such as a mouse.

If a velocity vector is specified and the position of the specified velocity vector is the start point of the vector, the position of the start point of the vector is changed to the current position of the cursor. Similarly, if the specified position is the end point of a vector, the position of the end point of the vector is changed to the current position of the cursor. If the specified position is neither the start point nor the end point of the vector, the vector is translated in parallel to follow the movement of the cursor. If the line of a path is specified, the velocity vectors at both the start and end points of the path are translated in parallel to cause the path and velocity vectors to follow the movement of the cursor.

The motion path is obtained using the velocity vectors set in the manner described above in the following manner.

The coordinates of the start and end points of the set vectors are assumed as shown in Fig. 3.

A velocity vector at the starting point frame (t = T0) of the path has

the vector starting point coordinates (X0s, Y0s, Z0s)

and

the vector endpoint coordinates (X0e, Y0e, Z0e) (1).

A velocity vector at the endpoint frame (t = Tn) of the path has

the vector starting point coordinates (Xns, Yns, Zns)

and

the vector endpoint coordinates (Xne, Yne, Zne) (2).

The entered and determined speeds can be calculated as follows.

The speed of the starting point frame (t = T0) of the path is

V0x = (X0e - X0s)/K

V0y = (Y0e - Y0s)/K

V0z = (Z0e - Z0s)/K... (3).

The speed of the endpoint frame (t = Tn) of the path is

Vnx = (Xne - Xns)/K

Vny = (Yne - Yns)/K

Vnz = (Zne - Zns)/K ... (4).

An interpolation of the path is performed using the following third order polynomial using the time as a parameter.

X = AX · t³ + BX · t² + CX · t + Dx

y = Ay t³ + By t² + Cy t + Dy

z = Az · t³ + Bz · t² + Cz · t + Dz... (5)

Using the path equations given above, the velocity is determined by one-time differentiation as shown below.

Vx = 3 · Ax · t² + 2 · Bx · t + Cx

Vy = 3 · Ay · t² + 2 · By · t + Cy

Vz = 3 · Az · t² + 2 · Bz · t + Cz ... (6)

Equations (1) and (2) for the positions of the start and end points and equations (3) and (4) for the velocities at the positions of the start and end points are substituted into equations (5) and (6) to obtain twelve equations with twelve unknowns, which uniquely determine the unknowns Ax, Bx, Cx, Dx, Ay, By, Cy, Dy, Az, Bz, Cz and Dz.

The path can be obtained from equation (5) by changing the time from t = T0 to t = Tn. By mapping the positions for each unit of time on the screen, a path line can be drawn on the screen as the location of the path.

The processing for drawing a path line described above is executed each time the mouse coordinates change, thereby enabling dynamic change of the path and determination of the path upon detection of the movement point of an object.

Fig. 4 sets out the structure of the path data management. Each object is managed by an object management node 401 in the object data storage unit 204. The movement path of an object can be searched in the object management node 401, and the movement path is stored as a list 402 of key frame data in the movement data storage unit 205. Each node of the list of key frame data corresponds to each set key frame, and the node sets a time for the key frame, the start and end points of a velocity vector, a pointer to the next key frame, and a pointer to the parameter table 403 for the obtained path. The parameter table is identified by the preceding and following key frame nodes.

The movement path set and displayed on the display screen 101 can be variably determined more finely, as shown in Figs. 5a to 5c. Fig. 5a shows a path 500 already displayed on the display screen 101, a start point 511, a speed 512 at the start point, an end point 521, and a speed 522 at the end point. First, as shown in Fig. 5b, a new key frame is determined. The operator inputs a position 501 at which the path is to be corrected or changed via the input device, the position being thereby displayed on the display screen. The time point for the determined point can be obtained from the equation (5). The time point is used as the time point for the new key frame, and a new key frame node is generated and inserted into the list of key frame data at the position corresponding to the time point. The velocity vector data at this time can be obtained using the time from the equation (6). The obtained velocity vector 502 is displayed at the determined position on the display screen. The position 501 to be changed can be displayed at the same time that the calculated velocity vector 502 is displayed.

The processing for changing a velocity vector is carried out in the same way as described above. However, it should be noted that the velocity vector to be changed is used both as end point data of the path extending from the previous key frame and as stretches, and is processed as the start point data of the path extending to the subsequent key frame, thereby enabling simultaneous change of the preceding and subsequent paths. With this construction, the paths and speeds before and after the newly set key frame can be smoothly coupled. For example, as shown in Fig. 5, when changing the speed 502 to a speed 503, a new path 504 can define a smooth movement. As shown in Fig. 5c, the path 500 and the new path 504 can be displayed simultaneously. Here, it is convenient to display the path 500 in the form of a fine line, a dashed line or in a first color and the second path 504 in the form of a bold line, a solid line or in a second color in order to make them distinguishable for the operator. Or only the path 504 can be displayed.

On the other hand, if the motion is to be changed rapidly, two key frames with different velocity vectors are set for the same time. The operator determines whether the motion is to be coupled smoothly or rapidly. If the position of the end point and a time for a certain path are somewhat close to the position of the start point and the time of another path, and if the operator selects a smooth coupling between them, the management of the two paths is changed to the management of one path. Namely, one of the key frame nodes 402 is deleted to manage the end point and the start point as if they were obtained from the same key frame node.

A moving picture is created in the following way. First, the operator enters an instruction to execute a trick sequence via the control panel 105. It is assumed that the number of frames per second is set to N frames per second in advance. At every 1/Nth time unit after the start of the trick sequence, it is determined which parameter table 403 between the key frame nodes 402 is used for an object. The coordinates of the position of the object are determined using the data in the determined parameter table from the equation (5). The above-described processes are repeated until the trick sequence is completed. In this way, the object moves as time passes, thereby realizing a trick sequence.

By using the motion path generating apparatus and method according to the present embodiment, it is possible to define moving images for use in industrial product presentation. For example, as shown in Fig. 6, the motion of an actual product at each part 601, 602, the motion of a camera 603, and the motion of a light source 604 are determined according to the method according to the embodiment. The product, the camera, and the light source correspond to the object described above, and their motion path is controlled using velocity vectors. The discontinuity of the motion, particularly the motion of the camera, is significantly reflected to the sense of sight, and in this connection the method according to the embodiment offers very advantageous effects.

Another embodiment of the present invention will be described with reference to Fig. 7. A shape input and processing unit 701 is a unit for inputting a three-dimensional shape. The shape input and processing unit 701 performs an affine transformation of the inputted shape. An attribute setting unit 702 interactively sets the attributes defined by the shape input and processing unit 701. nated shape data. The term "attribute" as used herein includes color specific to an object, a reflection attribute of the display, and a method of performing masking. A camera attribute and a light source attribute are also set interactively. The camera attribute includes virtual camera parameters used in displaying an image, that is, a view angle, a focus length, and a shutter speed. The light source attribute includes the type of light source, that is, an attribute for designating either a collimated light source, a point light source, and a spotlight light source, and the color and intensity of the emitted light. A motion setting unit 703 sets the movements of all objects. The motion of an object is represented by the position and the direction of view of an object at a certain time. The movements of the camera and light source are set in approximately the same way as those of an object. The motion setting unit 702 also sets an attribute that changes with time, operating in parallel with the attribute setting unit 702. An image processing unit 704 generates a moving image using the data defined by the shape input and processing unit 701, the attribute setting unit 702, and the motion setting unit 703.

Next, a method for determining the specific color of an object, the surface reflection attribute and the light source attribute will be described, which method is used with this embodiment. In the actual stage, the properties of light reflected from the surface of an object depend not only on the properties of the light illuminating the object, but also on the properties of the surface of the object. In the field of computer graphics, a desired Obtain image quality of a material using the characteristics of the surface of an object. Light reflected from the surface of an object is classified into scattered light and specular light. The scattered light is the components of light that have once penetrated into an object and are then emitted from the surface of the object in one direction. The specular light is the components of light that are reflected from the surface of an object in a specular manner. In this embodiment, using the following equation and taking the above-described circumstances into consideration, the luminance of each point on the surface of an object is determined.

I = Ib · Ka + lf Kd · cos(A) + If · Ks · W(B) + Ks · R(C) + Kt · T(D) ... (7)

In equation (7), I represents a certain luminance on the surface of an object, If and Ib represent a parameter indicating the properties of a light source, and Ka, Kd, Ks and Kt represent a parameter indicating the properties of the surface of an object. Equation (7) is calculated for each color component independently.

The second term of equation (7) is a term representing Lambert's cosine law, which is applied when light from a light source is perfectly scattered and reflected. In the second term, If is a factor indicating the color of the light source, Kd is a factor indicating the intensity of a scattered reflection, and A in cos(A) is an angle between a normal line on the object surface and the direction of the light source viewed from the surface of the object. This term indicates the components of the color specific to an object, such as plastic or plaster. The first term of equation (7) indicates the components of the ambient light other than the light source and is used to prevent a section of an object turns black when the portion is not directly illuminated by the light source. In the first term, Ib is a factor indicating the color and intensity of the ambient light, and Ka is a factor indicating the intensity of reflection of the ambient light. The third term of equation (7) gives the components of the specular light and is applied in a case where light from the light source is reflected from the surface of the object in a mirror-like manner. In the third term, If has the same value as in the second term and indicates the color of the light source. Ks is a factor indicating the intensity of a specular reflection, B in W(B) is an angle between the direction of a viewing angle and the direction of a normal reflection on the mirror surface, and W is a function indicating attenuation when the viewing angle shifts from the direction of the normal mirror reflection. The fourth term of equation (7) gives the components of an image of another object reflected from the surface of the object. In the fourth term, Ks has the same value as in the third term and is a factor indicating the intensity of a specular reflection, R(C) is a factor indicating an image reflected on the surface of the object, the factor being determined by a method such as a ray tracing method. The fifth term of equation (7) indicates the components of light transmitted through an object. In the fifth term, Kt is a factor indicating the intensity of transmitted light, T(D) is a factor indicating an image of the transmitted light determined by a method such as a ray tracing method, taking into account a refractive index and the like.

The specular reflection components and the reflected image components play an important role in realizing the image quality of the material of an object. For example, the specular reflection components of an object such as plastic have the same color as a light source, and those of metal, solid color, and the like have a color different from that of a light source. For example, when red plastic is illuminated with a white light, the specular reflection components become white, whereas when copper is illuminated with the same white light, the specular reflection components become red.

A practical system for determining luminance on an object is described with reference to Fig. 8. An object-specific color setting device 801 determines the specific color of an object. For example, to realize the material image quality of red plastic or copper, red is set as the specific color of the object. The object-specific color setting device 801 uses, for example, three primary colors, red, green and blue, and the operator assigns their intensities to realize a desired color tone. A computer presents selectable possible colors to the operator. Here, the object-specific color setting device 801 recalls a combination of stored red, green and blue tones to use as object-specific colors when the operator selects one of the possible colors. A surface reflection attribute device 802 receives the object-specific colors and calculates the parameters Ka, Kd, Ks and Kt of equation (7).

Fig. 9 shows the details of the surface reflection attribute adjustment device 802 for adjusting a surface reflection attribute. According to Fig. 9, an ambient light reflection intensity adjustment unit 901 receives the specific color of an object and modulates the intensity component to calculate Ka in the equation (7). Modulation of the intensity component can be achieved, for example, by first converting the object-specific color to the HLS color model and then adjusting the brightness component. A scattered reflection intensity adjustment unit 902 receives the object-specific color and modulates the intensity component to calculate Kd in the equation (7). A metal image quality adjustment unit 903 receives the object-specific color and modulates the saturation component. Modulation of the saturation component can be achieved, for example, by first converting the object-specific color to the HLS color model and then adjusting the saturation component. A specular reflection intensity adjustment unit 904 receives the specific color of the saturation-modulated object and modulates the intensity component to calculate Ks in the equation (7). A transmitted light intensity adjustment unit 905 receives the object-specific color and modulates the intensity component to calculate Kt in the equation (7). Ka, Kd, Ks, and Kt are vector information representing color information, and are represented, for example, by the intensity of each component of red, green, and blue.

For a surface reflection attribute setting unit, a method may be used in which a computer presents selectable choices for a surface reflection attribute to the operator. Here, when the operator selects one of the choices, the object-specific color input to the surface reflection attribute setting unit 802 and the parameters specified by an operator's instruction are used to calculate and output the parameters Ka, Kd, Ks and Kt.

Fig. 10 shows a device for setting a light source attribute. A light source specific color setting unit 1001 determines the specific color of a light source. The light source specific color setting unit 1002 uses three primary colors, red, green and blue, and the operator assigns their intensities to realize a desired color tone. A computer presents selectable possible colors to the operator. Here, when the operator selects one of the choices, the light source specific color setting unit 1001 calls up a combination of the stored red, green and blue tones for use as the light source specific colors. A light source intensity setting unit 1003 receives the light source specific color and modulates the intensity component to calculate If in equation (7). An ambient light color setting unit 1004 receives the light source specific color and a background color and performs interpolation between them to output the result. An ambient light intensity setting unit 1005 receives data from the ambient light color setting unit 1004 and modulates the intensity component to calculate Ib in equation (7).

Fig. 11 shows an example of a display on the display screen 101, showing a display section that serves as a user interface for setting an object-specific color and a surface reflection attribute. A set of three sliders for hue, brightness and saturation is used for color representation in the HLS color model and for specifying an object-specific color. The set of sliders has the function of providing a type of symbol. Similarly, a set of three sliders for red, green and blue is used for color representation in the RGB color model and for specifying an object-specific color. The set of sliders for hue, brightness and saturation is connected to the set of sliders for red, green and blue in such a way that when one set is changed, the other is also changed, maintaining a balance between them. A slider for adjusting the intensity of the Reflection of ambient light is used to determine the parameter Ka by changing the brightness component of an object-specific color, as shown in Fig. 12. Fig. 12 shows a cross-section of an HLS color model. The colors on a cross-section have the same hue, and the cross-section includes an object-specific color. As the brightness component is changed, the value of Ka is continuously changed from the object-specific color to black, as shown by a bold line. A slider for adjusting the intensity of a scattered reflection determines Kd by changing the brightness component of an object-specific color, as also shown in Fig. 12. A slider for adjusting the roughness of the surface is a slider for determining the range of the surface reflection components. A slider for adjusting the image quality of a metal material is a slider for changing the saturation component of an object-specific color, as shown by a bold line in Fig. 13. The saturation component is changed from the object-specific color to an achromatic color or gray. When the slider is moved toward the metal side, the output changes to the object-specific color, whereas when the slider is moved toward the plastic side, the output changes to an achromatic color. A slider for adjusting the intensity of specular reflection determines Ks by changing the brightness component of the color determined by the image quality slider of the metal material, as shown by dashed lines in Fig. 13. A slider for adjusting the intensity of transmitted light determines Kt by changing the brightness component of an object-specific color, as shown in Fig. 12. A slider for adjusting a refractive coefficient is a slider for adjusting the refractive coefficient of a transparent object.

Referring to Fig. 11, an object-specific color setting menu is a menu used to select the specific color of an object. When selected by the operator, a pre-stored specific color is called up and set on each slider. A surface reflection attribute setting menu is a menu used to select a surface reflection attribute. When selected by the operator, a pre-stored parameter is called up and set on each slider so that Ka, Kd, Ks, Kt, the surface roughness and the refraction coefficient are set on the respective sliders. The operator can instruct registration of the object-specific color or the surface reflection attribute set on the sliders in the corresponding menu.

Fig. 14 shows an example of a display on the display screen 101, showing a display section that serves as a user interface for adjusting a light source attribute. A set of three sliders for hue, brightness and saturation is used for color representation in the HLS color model and for specifying the specific color of a light source. The set of sliders has the function of providing a type of icon. Similarly, a set of three sliders for red, green and blue is used for color representation in the RGB color model and for specifying the specific color of a light source. The set of sliders for hue, brightness and saturation is connected to the set of sliders for red, green and blue such that changing one of the sets also changes the other while maintaining coordination between them. A slider for the intensity of the light source is used to determine If by changing the brightness component of a light source specific color, as also shown in Fig. 12. A slider for adjusting the color of the ambient light is a slider slider for performing interpolation between the light source-specific color and a background color, as shown in Fig. 15. When the slider is moved toward the background color side, the color of the ambient light is changed to the background color, whereas when the slider is moved toward the light source-specific color side, the color of the ambient light is changed to the light source-specific color. A slider for adjusting the intensity of the ambient light determines Ib by changing the brightness component of the color determined by the slider for adjusting the color of the ambient light, as shown by dashed lines in Fig. 15. A slider for setting a mode of the light source sets the mode of a light source.

As shown in Fig. 14, a light source attribute setting menu is a menu used to select a light source attribute. When selected by the operator, a pre-stored parameter is called and set on each slider to determine Ib, If and the type of a light source. The operator can give an instruction to register the light source attributes set on the sliders in the menu.

Next, a method of combining shape data and a method of assigning motion using the above-described embodiment will be described. Each shape data has its particular coordinate system. Each shape is defined using its particular coordinate system. Each shape data is referred to as component data herein, and the coordinate system for each shape data is referred to as component coordinate system herein. A hierarchical structure is set for all components of an object as shown in Fig. 16. The position in each component coordinate system is referred to as position in an initial coordinate system. A virtual component called a world is provided such that an absolute position of a component can be determined by setting a hierarchical structure between the world and the components. For moving a component, there are a method for moving a component itself in its component coordinate system and a method for moving the position of the coordinate system of a respective component in its initial coordinate system. The movement of an object is expressed by the latter method, ie by changing the position of the coordinate system of a respective component in its initial coordinate system.

A light source for a camera is not defined as a specific but as a general component with a camera attribute or light source attribute. It is therefore possible to determine the positions of a camera and a light source by means of motion determination using a hierarchical structure. A camera, a light source and components are collectively referred to as an object. A camera and a light source each have a camera coordinate system and a light source coordinate system, similar to components. These coordinate systems and the coordinate systems of the components are collectively referred to as an object coordinate system.

In this embodiment, the motion of an object is always expressed as the motion of the object's object coordinate system in the object coordinate system of the original object. The motion of an object is processed by dividing it into a change in position and a rotation of the object.

As shown by a display example on the display unit 101 shown in Fig. 17, the position change is determined by determining a passage position of a object at a certain point in time or by determining a passing position and the magnitude and direction of a velocity at a certain point in time. Such determinations are made several times and interpolation is performed between respective specified points, which serve as start and end points, thereby determining the total change in position and velocity. The interpolation method is described in detail below.

(1) Position and velocity information are given for both the start and end points.

The positions of the start and end points of an object with respect to the origin of the object coordinate system are given by (Pxs, Pys, Pzs) and (Pxe, Pye, Pze) in the object's initial coordinate system, respectively, and the velocities at the start and end points are given by (Vxs, Vys, Vzs) and (Vxe, Vye, Vze) in the object's initial coordinate system, respectively. The location can be expressed using the X, Y, and Z axes given by a third-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

X = (2 · Pxs - 2 · Pxe + Vxs + Vxe). t³ + (-3 · Pxs + 3 · Pxe - 2 · Vxs - Vxe) · t² + Vxs · t + Pxs

Y = (2 · Pys - 2 - Pye + Vys + Vye) · t³ + (-3 · Pys + 3 · Pye - 2 · Vys - Vye) · t² + Vys · t + Pys

Z = (2 · Pzs - 2 · Pze + Vzs + Vze) · t³ + (-3 · Pzs + 3 · Pze - 2 · Vzs - Vze) · t² + Vzs · t + Pzs ...(8)

(2) Position and speed information is given for the starting point and position information is given for the end point.

The positions of the start and end points of an object with respect to the origin of the object coordinate system are given by (Pxs, Pys, Pzs) and (Pxe, Pye, Pze) in the object's initial coordinate system, respectively, and the velocity at the start point is given by (Vxs, Vys, Vzs) in the object's initial coordinate system. The location can be expressed using the X, Y, and Z axes given by a second-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = (-Pxs + Pxe - Vxs) · t² + Vxs · t + Pxs

Y = (-Pys + Pye - Vys) · t² + Vys · t + Pys

Z = (-Pzs + Pze - Vzs) · t² + Vzs · t + Pzs

... (9)

(3) Position information is given for the starting point and position and speed information is given for the end point.

The positions of the start and end points of an object with respect to the origin of the object coordinate system are given by (Pxs, Pys, Pzs) and (Pxe, Pye, Pze) in the initial coordinate system of the object, respectively, and the velocity at the end point is given by (Vxe, Vye, Vze) in the initial coordinate system of the object. The location can be determined using the coordinates given by a second order parametric representation of t given X, Y and Z axes. Assuming that the location changes from the position of the starting point at time t = 0 to the position at the end point at time t = 1, the equations for the interpolation are:

X = (Pxs - Pxe + Vxs) · t² + (-2 · Pxs + 2 · Pxe - Vxe) t + Pxs

Y = (Pys - Pye + Vys) · t² + (-2 · Pys + 2 · Pye - Vye) · t + Pys

Z = (Pzs - Pze + Vzs) · t² + (-2 · Pzs + 2 · Pze - Vze) · t + Pzs

...(10)

(4) Position and speed information is given for the starting point and speed information is given for the end point.

The position of the start point of an object with respect to the origin of the object's coordinate system is given by (Pxs, Pys, Pzs) in the object's initial coordinate system, and the velocities at the start and end points are given by (Vxs, Vys, Vzs) and (Vxe, Vye, Vze) in the object's initial coordinate system, respectively. The location can be expressed using the X, Y, and Z axes given by a third-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = (-Vxs + Vxe)/2 · t² + Vxs t + Pxs

Y = (-Vys + Vye)/2 · t² + Vys · t + Pys

Z = (-Vzs + Vze)/2 · t² + Vzs · t + Pzs

...(11)

(5) Velocity information is given for the starting point and position and velocity information is given for the end point.

The position of the end point of an object with respect to the origin of the object's coordinate system is given by (Pxe, Pye, Pze) in the object's initial coordinate system, and the velocities at the start and end points are given by (Vxs, Vys, Vzs) and (Vxe, Vye, Vze) in the object's initial coordinate system, respectively. The location can be expressed using the X, Y, and Z axes given by a third-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = (-Vxs + Vxe)/2 · t² + Vxs · t + Pxe - (Vxs + Vxe)/2

Y = (-Vys + Vye)/2 · t² + Vys · t + Pye - (Vys + Vye)/2

Z = (-Vzs + Vze)/2 · t² + Vzs · t + Pze - (Vzs + Vze)/2

...(12)

(6) Position and speed information are given for the starting point.

The position of the starting point of an object with respect to the origin of the object coordinate system is given by (Pxs, Pys, Pzs) in the initial coordinate system of the object, and the velocity at the starting point is given by (Vxs, Vys, Vzs) in the initial coordinate system. stem of the object. The location can be expressed using the X, Y and Z axes given by a first order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for the interpolation are:

X = Vxs · t + Pxs

X = Vxs · t + Pxs

X = Vxs · t + Pxs

...(13)

(7) Position and velocity information are given for the end point.

The position of the end point of an object with respect to the origin of the object's coordinate system is given by (Pxe, Pye, Pze) in the object's initial coordinate system, and the velocity at the end point is given by (Vce, Vye, Vze) in the object's initial coordinate system. The location can be expressed using the X, Y, and Z axes given by a first-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = Vxe · t + (Pxe - Vxe)

Y = Vye · t + (Pye - Vye)

Z = Vze · t + (Pze - Vze)

... (14)

(8) Position information is provided for both the start and end points.

The positions of the start and end points of an object with respect to the origin of the object's coordinate system are given by (Pxe, Pye, Pze) and (Pxe, Pye, Pze) in the object's initial coordinate system, respectively. The location can be expressed using the X, Y, and Z axes given by a first-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = (-Pxs + Pxe) · t + Pxs

Y = (-Pys + Pye) · t + Pys

Z = (-Pzs + pze) · t + Pzs

...(15)

(9) Position information is given for the start point and speed information is given for the end point.

The position of the start point of an object with respect to the origin of the object's coordinate system is given by (Pxs, Pys, Pzs) in the object's initial coordinate system, and the velocities at the end point are given by (Vxe, Vye, Vze) in the object's initial coordinate system. The location can be expressed using the X, Y, and Z axes given by a first-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = Vxe · t + Pxs

Y = Vye · t + Pys

Z = Vze · t + Pzs

...(16)

(10) Speed information is given for the starting point and position information is given for the end point.

The position of the end point of an object with respect to the origin of the object's coordinate system is given by (Pxe, Pye, Pze) in the object's initial coordinate system, and the velocity at the start point is given by (Vxs, Vys, Vzs) in the object's initial coordinate system. The location can be expressed using the X, Y, and Z axes given by a first-order parametric representation of t. Assuming that the location changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the equations for interpolation are:

X = Vxs · t + (Pxe - Vxs)

Y = Vys · t + (pye - Vys)

Z = Vzs · t + (Pze - Vzs)

...(17)

(11) Position information is provided for the start point or the end point.

The positions of the start and end points of an object in relation to the origin of the object's coordinate system do not change in the object's initial coordinate system. The positions do not move.

(12) For both the start and end points, velocity information is given, for the start point, velocity information is given, or for the end point, velocity information is given.

In this case, no equations for interpolation can be determined, so such an assignment is classified as an error.

In practical use, a desired motion is set by successively coupling the interpolation equations described above. When coupling the equations for interpolation, the end point coordinates obtained by one set of interpolation equations must agree with the start point coordinates obtained by the next set of interpolation equations. In other words, the start point coordinates obtained by a set of interpolation equations must always agree with the end point coordinates obtained by the previous set of interpolation equations that is to be coupled with the first set.

Next, a user interface for setting a motion will be described. In this embodiment, a motion path such as that shown in Fig. 17 is displayed on the screen of the display device 101. In this embodiment, a motion path of an object is set by setting the position and speed of an object at each control timing. The set path is called a motion path. The control timing refers to an appropriate timing set by the operator. A user interface for changing the control timings will be described later. The position of an object at a control timing is called a control position, and this position is set by the operator. The speed of an object immediately before a control timing is called the input-side control speed. The speed of an object immediately after a control timing is called the output-side control speed. The same speed used jointly as the input-side and output-side control speeds is called the common control speed.

To input a control position, an input side control speed, an output side control speed, a common control speed or a combination of these values at each control time, an appropriate mode is selectively set. Which mode is set at each control time, i.e. which input is permitted among the control position, the input side control speed, the output side control speed and the common control speed, can be identified by distinguishably displaying a black circle, an arrow or a specific color on the screen on which the motion path is displayed.

To define a motion path by coupling a plurality of the above-described interpolation equations to a plurality of control timings set in advance, a single representative control timing is set. It is always necessary to set a control position at the representative control timing. When determining a motion path after the representative control timing, the end point coordinates obtained by the interpolation equations for an interpolation section before the interpolation section for the object should always be set to the same values as the start point coordinates obtained by the interpolation equations for the interpolation section for the object. In other words, the Interpolation calculation proceeds to future times. Therefore, the mode for such interpolation is only the mode which allows the position of an object at the start time to be input among the above-described modes. When determining a motion path before the representative control time, the start point coordinates obtained by the interpolation equations one interpolation section after the interpolation section for the object should always be made to agree with the end point coordinates obtained by the interpolation equations for the interpolation section for the object. In other words, the interpolation calculation proceeds to the past times. Therefore, the mode for such interpolation is only the mode which allows the position of an object at the end point to be input among the above-described modes. When the input control speed is set for the first control time, the interpolation equations (13) described above can be used for the period before the control time. Similarly, if the output control speed is set at the last control timing, the interpolation equations (12) described above can be used for the period after the control timing.

A method of setting a control position will be described with reference to Figs. 18a and 18b. Figs. 18 to 23 show examples of displays on a CRT display 101 serving as a display device. If the mode at a certain control time is a mode that allows input of a control position, such a mode can be indicated, for example, by using a large black circle at the control position or a certain color. The user (not shown) can move the black circle indicating the control position using an input device such as a position indicator or the like. The movement path changes when the control position is moved and the resulting motion path is immediately displayed.

A method for setting an input-side control speed is described with reference to Figs. 19a and 19b. When the input of an input-side control speed is permitted, the operator is informed of such a circumstance by, for example, using an arrow representing the input-side control speed or a specific color. The operator moves the end of the vector representing the input-side control speed to set an input-side control speed. The motion path changes when the input-side control speed is set, and the resulting motion path is immediately displayed. However, if the control timing for setting the input-side control speed is after the representative control timing and the mode is a mode that does not require a control position, the updated motion path is displayed after setting the input-side control speed because the position of the object moves at the control timing when the input-side control speed is changed.

A method for setting an output control speed is described with reference to Figs. 20a and 20b. When the input of an output control speed is permitted, the operator is notified of this fact, for example, by using an arrow representing the output control speed or a specific color. The operator moves the tip of the vector representing the output control speed to set a desired output control speed. The movement path is changed when setting the output control speed, and the resulting Motion path is displayed immediately. However, if the control timing for setting the output side control speed is before the representative control timing and the mode is a mode that does not require a control position, the updated motion path is displayed after setting the output side control speed because the position of the object at the control timing moves when the output side control speed is changed.

When a common control speed is set, the object moves smoothly because there is no change in the movement speed before and after the control timing. A method for setting a common control speed is described with reference to Figs. 21a and 21b. When the input of a common control speed is permitted, the operator is notified of this fact, for example, by using an arrow representing the common control speed or a specific color. The operator moves the tip of the vector representing the common control speed to set a desired common control speed. The movement path changes when the common control speed is set, and the resulting movement path is immediately displayed. However, when the control timing mode for setting the common control speed is a mode that does not require a control position, the updated movement path is displayed after setting the common control speed because the position of the object is moved at the control timing when the common control speed is changed.

An interpolation mode for interpolating a section between adjacent control points is determined depending on whether an output control speed and/or a control position for starting point are specified or whether an input-side control speed and/or a control position are specified for the end point. Even if no control position is specified for a control timing after the representative control timing, the same interpolation mode is used as when a control position is specified for the start point. This is because the control position at the end point of the preceding interpolation section is used as the control position at the start point of the interpolation section in question. Similarly, if no control position is specified for a control timing before the representative control timing, the same interpolation mode is used as when a control position is specified for the end point. This is because the control position at the start point of the subsequent interpolation section is used as the control position at the end point of the interpolation section in question. In view of the foregoing, although the following description concerns a case where no control position is specified for the start point for a control timing after the representative control timing, approximately the same description is applicable as in a case where a control position is specified for the start point. Similarly, although the following description applies to a case where no endpoint tax position is specified for a tax point prior to the representative tax point, approximately the same description applies to a case where an endpoint tax position is specified.

First, a description is given for each interpolation section according to the representative control time. If an output control speed is specified for the start point and a control position and an input control speed are specified for the end point, the interpolation equations (8) described in section (1) are used. If an output control speed is specified for the start point, speed and a control position are specified for the end point, the interpolation equations (9) described in section (2) are used. If no information is specified for the start point and a control position and an input control speed are specified for the end point, the interpolation equations (10) described in section (3) are used. If an output control speed is specified for the start point and an input control speed is specified for the end point, the interpolation equations (11) described in section (4) are used. If an output control speed is specified for the start point and no information is specified for the end point, the interpolation equations (13) described in section (6) are used. If no information is specified for the start point and a control position is specified for the end point, the interpolation equations (15) described in section (8) are used. If no information is specified for the start point and an input control speed is specified for the end point, the interpolation equations (16) described in section (9) are used. If no information is given for the start point or the end point, the interpolation equations described in section (11) are used.

Next, a description is given for each interpolation section before the representative control time. If a control position and an output control speed are specified for the start point and an input control speed are specified for the end point, the interpolation equations (8) described in section (1) are used. If a control position and an output control speed are specified for the start point and an input control speed are specified for the end point, the interpolation equations (10) described in section (3) are used. If a control position and an output control speed are specified for the start point and no information is specified for the end point, the interpolation equations (9) described in section (2) are used. If an output control speed is specified for the start point and an input control speed is specified for the end point, the interpolation equations (12) described in section (5) are used. If no information is specified for the start point and an input control speed is specified for the end point, the interpolation equations (14) described in section (7) are used. If a control position is specified for the start point and no information is specified for the end point, the interpolation equations (15) described in section (8) are used. If an output control speed is specified for the start point and no information is specified for the end point, the interpolation equations (17) described in section (10) are used. If no information is specified for either the start point or the end point, the interpolation equations (11) are used.

Furthermore, the interpolation equations (14) described in section (7) are used for an interpolation section before the first control time if an input-side control speed is specified for the first control time. If an output-side control speed is specified for the last control time, the interpolation equations (13) described in section (6) are used for an interpolation section after the last control time. If only one control time is specified and neither the input-side nor the output-side control speed is specified for the control time, the interpolation equations described in section (11) are used.

Fig. 22 shows a timeline editor for preparing a control point. Rectangles on a line to the right of the component name of an object are control point indicators for indicating the points of control points and a representative control timing indicator for indicating the point of a representative control timing. The indicators have the function of symbols. More specifically, according to Fig. 22, the control timings for an object named "camera", the control timings are set to 0, 3, 7 and 9 seconds. The representative control timing is set to 3 seconds. For the control timing at 0 s, a control position and an output side control speed are given. For the control timing at 3 s, a control position and an input and output side speed in the common mode are given. For the control timings at 7 and 9 s, only a control position is given.

To specify a time at which an object is displayed on a motion path, a current time indicator is used. When the current time indicator is moved using a position indicator or the like, the displayed object is moved on the motion path.

If the control timing indicator or the representative control timing indicator is moved right or left using a position indicator, the corresponding control timing can be changed. When a control timing is set, the movement path changes and the resulting movement path is displayed immediately. For example, as shown in Fig. 23, if a control timing is changed from 6 s to 7.5 s using a symbol, the displayed location in the upper portion of the frame is also changed.

It is possible to determine whether to set information for a control timing indicated by a control timing indicator or by the indicator for the representative control timing selected by an input device such as a position indicator. Namely, it is possible to determine whether to set information for a control position, an input-side control speed or an output-side control speed are to be set for a specific control time.

In the timeline editors shown in Figures 22 and 23, a new control timing can be set using a position indicator on a line to the right of a component name. A control timing indicated by a control timing indicator can be deleted by selecting its rectangle.

Next, a method for rotating an object is described. As described above, the rotation of an object, i.e., the viewing direction of an object, is expressed as the rotation of the object in the object coordinate system around the origin of the object coordinate system of an initial object. In this embodiment, a rotation axis refers to the coordinate system of an initial object. A rotation axis may refer to the coordinate system of the object itself.

As shown in Fig. 24, a rotation of an object is determined by a rotation angle and an angular velocity with respect to the X, Y and Z axes of an initial object. Such assignments are performed a plurality of times, and interpolation is performed between respective assigned points serving as start and end points, thereby obtaining the total rotation angles and angular velocities. The interpolation method is described in detail below.

(1) For both the start and end points, a rotation angle and an angular velocity are given.

The rotation angles for the start and end points of an object in the coordinate system of the object are given by (Rxs, Rys, Rzs) and (Rce, Rye, Rze) in the coordinate system of the original object, respectively, and the Angular velocities for the start and end points are given by (Wxs, Wys, Wzs) and (Wxe, Wye, Wze) in the coordinate system of the initial object, respectively. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = (2 · Rxs - 2 · Rxe + Wxs + Wxe) · t³ + (-3 · Rxs + 3 · Rxe - 2 · Wxs - Wxe) · t² + Wxs · t + Rxs

RY = (2 · Rys - 2 · Rye + Wys + Wye) · t³ + (-3 · Rys + 3 · Rye - 2 · Wys - Wye) · t² + Wys · t + Rys

RZ = (2 · Rzs - 2 · Rze + Wzs + Wze) · t³ + (-3 · Rzs + 3 · Rze - 2 · Wzs - Wze) · t² + Wzs · t + Rzs

...(18)

(2) A rotation angle and an angular velocity are given for the starting point and a rotation angle is given for the end point.

The angles of rotation for the start and end points of an object in the coordinate system of the object are given by (Rxs, Rys, Rzs) and (Rce, Rye, Rze) in the coordinate system of the original object, respectively, and the angular velocity for the start point is given by (Wxs, Wys, Wzs) in the coordinate system of the original object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parameter representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = (-Rxs + Rxe - Wxs) · t² + Wzs · t + Rxs

RY = (-Rys + Rye - Wys) · t² + Wzs · t + Rys

RZ = (-Rzs + Rze - Wzs) · t² + Wzs · t + Rzs

...(19).

(3) A rotation angle is given for the starting point, and a rotation angle and an angular velocity are given for the end point.

The angles of rotation for the start and end points of an object in the coordinate system of the object are given by (Rxs, Rys, Rzs) and (Rxe, Rye, Rze) in the coordinate system of the initial object, respectively, and the angular velocity for the end point is given by (Wxe, Wye, Wze) in the coordinate system of the initial object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = (Rxs - Rxe + Wxs) · t² + (-2 · Rxs + 2 · Rxe - Wxe) · t + Rxs

RY = (Rys - Rye + Wys) · t² + (-2 · Rys + 2 · Rye - Wye) · t + Rys

RZ = (Rzs - Rze + Wzs) · t² + (-2 · Rzs + 2 · Rze - Wze) · t + Rzs

... (20)

(4) A rotation angle and an angular velocity are given for the starting point, and an angular velocity is given for the end point.

The angle of rotation for the start point of an object in the coordinate system of the object is given by (Rxs, Rys, Rzs) in the coordinate system of the initial object, and the angular velocities for the start and end points are given by (Wxs, Wys, Wzs) and (Wxe, Wye, Wze) in the coordinate system of the initial object, respectively. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = (-Wxs + Wxe)/2 · t² + Wxs · t + Rxs

RY = (-Wys + Wye)/2 · t² + Wys · t + Rys

RZ = (-Wzs + Wze)/2 · t² + Wzs · t + Rzs

...(21)

(5) An angular velocity is given for the starting point, and an angle of rotation and an angular velocity are given for the end point.

The angle of rotation for the end point of an object in the coordinate system of the object is given by (Rxe, Rye, Rze) in the coordinate system of the original object, and the angular velocities for the start and end points are given by (Wxs, Wys, Wzs) and (Wxe, Wye, Wze) in the coordinate system of the original object, respectively. The angle of rotation can be determined using the X, Y and Z-axis. If it is assumed that the angle of rotation changes from the position of the starting point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = (-Wxs + Wxe)/2 · t² + Wxs · t + Rxe - (Wxs + Wxe)/2

RY = (-Wys + Wye)/2 · t² + Wys · t + Rye - (Wys + Wye)/2

RZ = (-Wzs + Wze)/2 · t² + Wzs · t + Rze - (Wzs + Wze)/2

...(22)

(6) A rotation angle and an angular velocity are given for the starting point.

The angle of rotation for the starting point of an object in the coordinate system of the object is given by (Rxs, Rys, Rzs) in the coordinate system of the initial object, and the angular velocity for the starting point is given by (Wxs, Wys, Wzs) in the coordinate system of the initial object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the starting point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = Wxs · t + Rxs

RY = Wys · t + Rys

RZ = Wzs · t + Rzs

... (23)

(7) A rotation angle and a rotation speed are specified for the end point.

The angle of rotation for the end point of an object in the coordinate system of the object is given by (Rxe, Rye, Rze) in the coordinate system of the initial object, and the angular velocity for the end point is given by (Wxe, Wye, Wze) in the coordinate system of the initial object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = Wxe · t + (Rxe - Wxe)

RY = Wye · t + (Rye - Wye)

RZ = Wze · t + (Rze - Wze)

...(24)

(8) A rotation angle is given for both the start and end points.

The angles of rotation for the start and end points of an object in the coordinate system of the object are given by (Rxs, Rys, Rzs) and (Rxe, Rye, Rze) in the coordinate system of the original object, respectively. The angle of rotation can be expressed using the X, Y and Z axes given by a parameter representation of t. It is assumed that the angle of rotation extends from the position of the start point at time t = 0 to the position of the end point at time point t = 1, the interpolation equations are:

RX = (-Rxs + Rxe) · t + Rxs

RY = (-Rys + Rye) · t + Rys

RZ = (-Rzs + Rze) · t + Rzs

... (25)

(9) A rotation angle is given for the starting point, and an angular velocity is given for the end point.

The angle of rotation for the start point of an object in the object's coordinate system is given by (Rxs, Rys, Rzs) in the coordinate system of the initial object, and the angular velocity for the end point is given by (Wxe, Wye, Wze) in the coordinate system of the initial object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the start point at time t = 0 to the position of the end point at time t = 1, the interpolation equations are:

RX = Wxe · t + Rxs

RY = Wye · t + Rys

RZ = Wze · t + Rzs

...(26)

(10) An angular velocity is given for the starting point, and an angle of rotation is given for the end point.

The angle of rotation for the endpoint of an object in the object's coordinate system is given by (Rxe, Rye, Rze) in the coordinate system of the initial object, and the angular velocity for the starting point is given by (Wxs, Wys, Wzs) in the coordinate system of the initial object. The angle of rotation can be expressed using the X, Y, and Z axes given by a parametric representation of t. Assuming that the angle of rotation changes from the position of the starting point at time t = 0 to the position of the ending point at time t = 1, the interpolation equations are:

RX = Wxs · t + (Rxe - Wxs)

RY = Wys · t + (Rye - Wys)

RZ = Wzs · t + (Rze - Wzs)

...(27)

(11) A rotation angle is given for the start or end point.

The angles of rotation for the start and end points of an object in the coordinate system of the object do not change in the coordinate system of the original object. There is no rotation.

(12) An angular velocity is given for both the start and end points, or an angular velocity is given for either the start or the end point.

In this case, no interpolation equations can be obtained, so that such an assignment is classified as an error.

In practical use, a desired rotational motion is set by successively coupling the interpolation equations described above. When coupling interpolation equations, the angle of rotation for the end point obtained by one set of interpolation equations must agree with the angle of rotation for the start point obtained by the next set of interpolation equations. In other words, the angle of rotation for the start point obtained by one set of interpolation equations must always agree with the angle of rotation for the end point obtained by the previous set of interpolation equations to be coupled with the first set.

The angle of rotation of an object at a control time that can be set by the operator is called the control angle of rotation. The angular velocity of an object immediately before a control time is called the input-side control angular velocity. The angular velocity of an object immediately after a control time is called the output-side control angular velocity. An equal angular velocity used jointly as the input-side and output-side control angular velocities is called the common control angular velocity.

To input a control rotation angle, an input-side control angular velocity, an output-side control angular velocity, a common control angular velocity or a combination of these values, an appropriate mode is selectively set at each control time. Which mode is set at each control time, that is, which input is allowed among the control rotation angle, the input-side control angular velocity, the output-side control angular velocity and the common control angular velocity, can be distinguished by displaying a black circle, an arrow or a specific color on the screen on which a motion path is displayed.

To define a rotation angle by coupling a plurality of the interpolation equations described above at a plurality of predetermined control timings, a single representative control timing for setting the rotation angle is set. The representative control timing for setting the rotation angle may be the same as the representative control timing used to assign a position of an object, or it may be different. It is always necessary to set a control rotation angle at the representative control timing for setting the rotation angle. When obtaining a rotation angle after the representative control timing for setting the rotation angle, the rotation angle for the end point obtained by interpolation equations one interpolation section before the interpolation section for the object must always be made to agree with the rotation angle for the start point obtained by interpolation equations for the interpolation section for the object. In other words, the interpolation calculation proceeds to a future timing. Therefore, the mode for such interpolation is only the mode that allows input of the rotation angle of an object at the start point among the modes described above. When obtaining a rotation angle before the representative control timing for setting the rotation angle, the rotation angle at the start point obtained by interpolation equations for one interpolation section before the interpolation section for the object must always be made to agree with the rotation angle at the end point obtained by interpolation equations for the interpolation section for the object. In other words, the interpolation calculation progresses to the past time. Therefore, the mode for such interpolation is only the mode among the modes described above that allows input of the rotation angle of an object at the end point. When the input side control angular velocity is set at the first control timing, the interpolation equations described in section (7) can be used for the period before the control timing. Similarly, when the output side control angular velocity is set at the last control timing, the interpolation equations described in section (6) can be used for the period after the control timing.

An interpolation mode for interpolating a section between adjacent control timings is determined depending on whether an output-side control angular velocity and/or a control rotation angle are given for the start point or an input-side control angular velocity and/or a control rotation angle are given for the end point. Even if no control rotation angle is given for a control timing after the representative control timing for setting the rotation angle, the same interpolation mode as that used when a control rotation angle is given for the start point is used. This is because the control rotation angle at the end point of the preceding interpolation section is used as the control rotation angle at the start point of the interpolation section in question. Similarly, even if no control rotation angle is given for a control timing before the representative control timing for setting the rotation angle, the same interpolation mode as that used when a control rotation angle is given for the end point is used. The reason for this is that the control rotation angle at the start point of the subsequent interpolation section is used as the control rotation angle at the end point of the interpolation section in question. In view of the above, although the following description concerns a case where no control rotation angle is given for the start point for a control timing after the representative control timing for setting the rotation angle, approximately the same description applicable to a case where a control rotation angle for the start point is given. Similarly, although the following description concerns a case where a control rotation angle for the end point is not given for a control timing before the representative control timing for setting the rotation angle, approximately the same description is applicable to a case where a control rotation angle for the end point is given.

First, a description is given for each interpolation section according to the representative control timing for setting the rotation angle. When an output-side control angular velocity is given for the start point and a control rotation angle and an input-side control angular velocity are given for the end point, the interpolation equations (18) described in section (1) are used. When an output-side control angular velocity is given for the start point and a control rotation angle is given for the end point, the interpolation equations (19) described in section (2) are used. When no information is given for the start point and a control rotation angle and an input-side control angular velocity are given for the end point, the interpolation equations (20) described in section (3) are used. When an output-side control angular velocity is given for the start point and an input-side control angular velocity is given for the end point, the interpolation equations (21) described in section (4) are used. If an output control angular velocity is given for the starting point and no information is given for the end point, the interpolation equations (23) described in section (6) are used. If no information is given for the starting point and a control angle of rotation is given for the end point, the interpolation equations (25) described in section (8) are used. If no information is given for the starting point and an input control angular velocity is given for the end point, the interpolation equations (25) described in section (9) are used. If information is not available for either the start point or the end point, the interpolation equations described in section (11) are used.

Next, a description is given for each interpolation section before the representative control time. If a control rotation angle and an output-side control angular velocity are given for the start point and an input-side control angular velocity are given for the end point, the interpolation equations (18) described in section (1) are used. If a control rotation angle and an input-side control angular velocity are given for the start point and an input-side control angular velocity are given for the end point, the interpolation equations (20) described in section (3) are used. If a control rotation angle and an output-side control angular velocity are given for the start point and no information is given for the end point, the interpolation equations (19) described in section (2) are used. If an output-side control angular velocity is given for the start point and an input-side control angular velocity is given for the end point, the interpolation equations (22) described in section (5) are used. If no information is given for the start point and an input control angular velocity is given for the end point, the interpolation equations (24) described in section (7) are used. If a control angle of rotation is given for the start point and no information is given for the end point, the interpolation equations (25) described in section (8) are used. If an output control angular velocity is given for the start point and no information is given for the end point, the interpolation equations (27) described in section (10) are used. If no information is given for either the start point or the end point, the interpolation equations described in section (11) are used.

Furthermore, if an input-side control angular velocity is given for the first control time, the interpolation equations (24) described in section (7) are used for an interpolation section before the first control time. If an output-side control angular velocity is given for the last control time, the interpolation equations (23) described in section (6) are used for an interpolation section after the last control time. If only one control time exists and neither an input-side nor an output-side control velocity is given for the control time, the interpolation equations described in section (11) are used.

It is possible to determine whether to set information for a control timing selected by a position indicator indicated by a control timing indicator on the timeline editors shown in Figs. 22 and 23. Namely, it is possible to determine whether to set a control rotation angle, an input-side control angular velocity, or an output-side control angular velocity for a certain control timing.

Instead of the method described above, another method of assigning an angle in which a constraint condition is introduced is used. According to this method of assigning an angle in which a constraint condition is introduced, information at a control timing is not used to assign an angle, but a constraint condition defined by another object is used. The following describes the constraint conditions used according to this embodiment.

(1) Condition for restricting a point

Information regarding a target object and a target point represented by a coordinate value in the coordinate system of the target object is input. When the world is assigned as a target object, a subject object is always oriented in the direction assigned in the absolute coordinate system. Such an assignment can be applied, for example, to a case where a camera is moved while shooting a car as shown in Fig. 25.

Figs. 25 to 28 show examples of displays on the screen of a CRT display 101 serving as a display device.

(2) Condition for restricting the line

Information is input regarding a target object and a straight target line represented by a straight line in the coordinate system of the target object. For example, as shown in Fig. 26, an object of interest is rotated so that it is always oriented in the direction of a straight line that is perpendicular to the straight target line and extends through the object of interest.

(3) Condition for restricting a level

Information is input regarding a target object and a target plane represented by a flat plane in the coordinate system of the target object. For example, as shown in Fig. 27, an object in question is rotated such that the viewing direction The object's orientation is always aligned in the direction of the normal line of the target plane.

(4) Condition for restricting the velocity vector

As shown in Fig. 28, an object in question is rotated, for example, in such a way that the viewing direction of the object is always aligned in the direction of movement, i.e. in the direction of the tangent of the movement path.

Fig. 29 shows an example of display of a basic operation frame on a CRT display 101 serving as a display device according to the embodiment. An operation is basically carried out using a cursor 2901 having switches and a keyboard 2902. First, a subject operation component is selected using the cursor 2901, and then an operation instruction is input. As a method of selecting a subject object for an operation using the cursor 2901, there are a method of selecting a subject object for operation by directly designating it with a cursor and pressing a switch, and a method of selecting a subject object for operation by designating a rectangular area containing the objects and selecting a plurality of objects at the same time. When the former method is used to select an object, the name of a selected subject object and the specific component number are displayed on a character display area described below. When other methods are used, all the components can be selected by designating an instruction for selecting all the components from a callable menu described below. or a single component can be selected by specifying a component name on a timeline editor. If a previously selected component is selected again, that component is placed in an unselected state.

The operation screen is used in either a four-way divided display mode or a non-divided display mode. In the four-way divided display mode, three triangular diagrams are displayed in the upper left area, the lower left area, and the lower right area, and an image as seen by a camera or a perspective view viewed from a selectable angle is selectively displayed in the upper right area. The upper right area is called the fourth level. The non-divided mode is a mode in which a desired display area of the four-way divided mode is enlarged and displayed on the entire screen area. A character display area at the upper end section is an area in which an instruction entered from the keyboard or one of the various statuses of the system is displayed. Four fixed menus at the right end section include a control menu for entering and displaying shapes, a menu for setting attributes, a menu for setting motions, and a menu for editing images. Each menu is displayed in normal brightness when the menu can be selected, and in a dark color when it cannot be selected. When a menu has a specific mode and is in a selectable state, a check mark is displayed in front of the menu name. As shown in Fig. 29, an invokable menu can be invoked by pressing a switch on the position indicator. The analysis and type of instructions contained in the invokable menu differ depending on the position of the position indicator when pressing a switch and depending on the mode. The menu displayed on The menu that can be called also contains only the instruction last selected in the four fixed menus.

Among the four fixed menus, the control menu for inputting and displaying shapes contains instructions for inputting shapes, deleting components, copying components, assigning output elements, magnifying components, rotating components, moving components, displaying grids, deleting grids, normal display, ordinary display, displaying a solid rectangle, no display, displaying rotation, viewing angle of a camera, snapshot storage, and reading snapshots. The function of each instruction is described below.

The shape input instruction is an instruction for inputting an externally defined three-dimensional shape. If the name of a file in which shape data is stored and the format of the shape data are specified, the shape data is obtained. Multiple components can be stored in the file, with the names of the components and their hierarchical structure stored and each component automatically assigned a unique component number. All components without a source element are controlled to have the world as their source element.

The delete component instruction is an instruction to completely delete an already selected component.

The copy component instruction is an instruction to create another component by dividing the shape data of an already selected component. A component created by this instruction shares the shape data with another component. Therefore, if an instruction to enlarge a component, an instruction to rotate a component, or an instruction to Component or an instruction to move a component is executed, the other components are influenced by the executed instruction.

The statement for assigning an output element is an instruction for assigning an output element to an already selected component. When the name of a component serving as an output element or a component number is entered, the hierarchical structure of the components is reconstructed.

The component enlargement instruction is an instruction to change the size of a component using the component's coordinate system as a reference. If the enlargement or reduction factor is entered for each axis of the component's coordinate system, the enlargement or reduction is carried out by the corresponding factor.

The rotate component instruction is an instruction to rotate a component using the component's coordinate system as a reference. When the rotation angle is entered for each axis, a rotation is performed.

The instruction to move a component is an instruction to move a component using the coordinate system of the component as a reference. When the movement amount is entered for each axis, a parallel movement is performed.

The instruction to display a grid is an instruction to display a reference coordinate system and a reference plane of an already selected component.

The delete mesh statement is an instruction to delete a reference coordinate system and a reference plane of an already selected component.

The normal display instruction is an instruction to display a component coordinate system of only an already selected component in a normal position. When this instruction is executed under the condition that no component is selected, the coordinate system of the world is displayed in the normal position. The normal position is a position in which a designated coordinate system becomes a reference coordinate system in which three triangular diagrams are displayed.

The normal display instruction changes a display mode of an already selected component to a normal display mode. The normal display instruction is an instruction for rendering an image using an attribute value assigned to each component. The attribute value is described in the description of the attribute setting menu.

The rectangular solid display instruction changes a display mode of an already selected component to a rectangular solid display mode. In the rectangular solid display mode, a rectangular solid is displayed in its specific color, which is obtained by drawing lines extending between maximum and minimum values on each axis in the component coordinate system of a component. The object-specific color is described in the description of the attribute setting menu.

The no display instruction changes the display mode of an already selected component to a no display mode. No display mode is a mode for suppressing the display of a particular component.

The instruction to rotate a display is an instruction to rotate a perspective view when it is displayed on the fourth level, thereby determining the three-dimensional position of an object and to support the setting of the location.

The camera angle of view instruction determines whether an image captured by a camera or a perspective view viewed from a selectable angle is displayed on the fourth layer. When an image captured by a camera is displayed, a check mark is displayed before the camera angle of view instruction.

The save snapshot statement is an instruction to save all currently processed data to a file. When the name of a file is entered, this instruction is executed.

The read snapshot instruction is an instruction to read data that has already been prepared. If the name of a file is entered, all currently prepared data is deleted once, and then the data from the specified file is read to enable preparation.

Among the four fixed menus, the attribute setting menu contains instructions regarding attribute editing, masking, camera assignment, and light source assignment. The function of each instruction is described below.

The Edit Attributes statement opens a surface attributes editor if an already selected object is a component, a camera attributes editor if the object is a camera, and a light source attributes editor if the object is a light source. If the statement is selected when no object is selected, the Surface Attributes Editor opens. Using the Surface Attributes Editor, it is possible to edit the surface attributes of a designated object. If multiple components are selected, the Surface Attributes Editor opens. ten, each component is assigned a surface attribute. Each editor is described below.

The masking instruction opens a masking editor for masking an already selected component. If multiple objects are selected, the same masking operation is performed for each object using a parameter determined by the masking editor.

The statement to assign a camera is an instruction to designate an already selected component as a camera. If another component was designated as a camera, such an assignment is deleted and the component designated by this statement is redesignated as a camera.

The light source assignment statement is an instruction to designate an already selected component as a light source. A component designated as a light source is displayed in a light source-specific color. If the statement is executed on a component that is already designated as a light source, such a light source assignment is deleted and the designated component becomes a normal component.

Among the four fixed menus, the menu for setting a motion contains instructions for displaying a location, deleting a location, displaying a timeline editor, editing a motion, and reading a motion. The function of each instruction is described below.

The instruction to display a location is an instruction to display the motion path of an already selected component.

Among the four fixed menus, the menu for processing an image contains instructions regarding processing the background, image synthesis, hardware image processing and software image processing.

Next, another embodiment of the present invention will be described.

In the actual stage, the properties of light reflected from the surface of an object depend not only on the properties of a light source but also on the properties of the surface of an object. In the field of computer graphics, the image quality of a desired material is obtained by expressing the properties of the surface of an object. Light reflected from the surface of an object is classified into scattered light and specular light. The scattered light is the components of light that have once penetrated into an object and are then radiated from the surface of the object in a direction. The specular light is the components of light that are reflected from the surface of an object in a mirror-like manner.

In the field of computer graphics, the following equation is generally used to determine the brightness or luminance of the surface of an object.

I = Ia · Ka + Id · Kd · cos(A) + Is · Ks · W(B)

...(28),

where

I: certain luminance on the surface of an object,

Ia, Ib, Is: parameters that indicate the properties of a light source,

Ka: intensity of ambient light,

Kd: intensity of scattered light,

Ks: Intensity of the reflected light.

The first term (the ambient light components) of equation (28) represents the ambient light components irradiated above the light source. This term is used to prevent a section not directly illuminated by the light source from becoming black.

The second term (the scattered light components) of equation (28) is a term representing Lambert's cosine law, which is applied when light from a light source is completely scattered and reflected. The value "A" in cos(A) is an angle between a normal line on the surface of an object and the direction of the light source as viewed from the surface of the object. The term indicates the components of color specific to an object, such as plastic or plaster.

The third term of equation (28) is an expression that indicates the reflected light components. The value "B" in W(B) is an angle between the direction of a viewing angle and the direction of normal reflection on the mirror surface, and W(B) is a function that indicates an attenuation when the viewing angle is shifted from the direction of normal mirror reflection. The reflected light components play an important role in expressing the image quality of the material of an object. For example, the reflected light components of an object made of plastic have the same color as the light source. Namely, when the light source emits white light, the reflected light from the plastic becomes white, and when the light source emits red light, the reflected light becomes red. On the other hand, those of metal, solid paint, and the like have a color different from that of the light source. If, for example, copper is illuminated with white light, the reflected light components have the color specific to copper, i.e. they are red.

Ka, Kd and Ks represent color vector information, each of which can be represented by a combination of R, G and B. A combination of Ka, Kd and Ks is enables the expression of images of different material qualities. However, a conventional method of determining a combination of R, G and B that determines Ka, Kd or Ks required considerable expertise. In this embodiment, Ka is not determined by a combination of R, G and B, but is determined by representing the color of an object in a (H, L, S) color model as (H, αaL, S), where 0 ≤ α ≤ 1. Similarly, Kd is determined by (H, αd, S), where 0 ≤ α d ≤ 1. Ks is determined by (H, αsL, βsS), where 0 ≤ α s ≤ 1 and 0 ≤ β s ≤ 1. A "matte" color is expressed by setting αs = 0. The color of plastic is expressed by setting βs = 0, and the color of metal is set by setting βs = 1. Each specific value of Ka, Kd, and Ks is converted into a combination of R, G, and B by a calculation by a computer. Ka and Kd are assigned a color depending on a color specific to an object, and the intensity of reflection can be adjusted independently of each parameter. Ks is assigned a color specific to an object, the color white, or an intermediate color to determine the intensity of reflection.

Fig. 30 shows the structure of the main part of a computer graphics system according to the embodiment of the present invention. An object-specific color determining device 1 determines the color specific to an object. For example, when an image of the material quality of red plastic or copper is to be realized, a "red" color is used as the object-specific color. The object-specific color determining device determines the color tone of an object using the three primary colors R, G and B and in accordance with the "color" and "intensity" assigned by the operator. In this embodiment, the operator can determine the color and intensity linearly using sliders, as described below with reference to Fig. 34. However, selectable possible colors can also be presented to the operator using a computer, and the color selected by the operator can be used as the object-specific color.

The details of a surface reflection attribute determining device 2 shown in Fig. 30 are shown in Fig. 31. The surface reflection attribute determining device 2 is composed of an ambient light intensity determining unit 3, a scattered light intensity determining unit 4, a metal image quality adjusting unit 5, and a reflected light intensity determining unit 6.

The ambient light intensity (Ka) determination unit 3 receives RGB data representing an object-specific color from the object-specific color determination device 1 and converts the received data into data in the HLS color model. Then, in the manner described above, using a value αa specified by the operator, (H, αaL, S) is determined and converted into data in the RGB color model to calculate Ka.

Similarly, the scattered light intensity (Kd) determination unit 4 converts the RGB data into HLS data. Then, using an operator-specified value of αd, (H, αdL, S) is determined and converted into the RGB model to calculate Kd.

Similarly, the metal quality image adjustment unit 5 receives RGB data and converts it into HLS data. Then, using a user-specified value of βs (H, L, βsS) is determined. The reflected light intensity (Kd) determination unit 6 determined using an operator-specified value of αa (H, αsL, (βsS)) and converts the value to data in the RGB color model to calculate Ks.

Fig. 32 shows a sphere illuminated by a single light source. The values Ka, Kd and Ks described above determine the area and brightness at each point of the sphere. According to Fig. 32, the ambient light component is determined by the parameter Ks to express a portion not directly illuminated by the light source. The scattered light component is determined by the parameter Kd to express a portion directly illuminated by the light source. The reflected light component is determined by Ks to express a portion where the light is reflected from the surface of the object in a mirror-like manner and impinges on the eyes.

Next, the determination of an object-specific color will be described. In determining a color, the three RGB colors are generally used to determine a hue by adjusting the color intensities. However, in this embodiment, an object-specific color is determined using the HLS color model. Fig. 33 illustrates an HLS color model. A color is identified by inputting three parameters including H (the hue), L (the brightness), and S (the saturation). The hue H takes a value from 0 to 360 degrees. 0 degrees represents "red," 60 degrees represents "yellow," 120 degrees represents "green," 180 degrees represents "cyan," 240 degrees represents "blue," and 300 degrees represents "magneta." The brightness L takes a value from 0.0 to 110. The hqert 0.0 represents "black," the value 1.0 represents white, the remaining values represent colors corresponding to the hue H and the saturation S. The saturation 5 takes a value from 0.0 to 1.0. The value 0.0 represents a "achromatic color", that is, "gray", and the value 1.0 represents a "pure color". By changing the saturation S, it is possible to continuously change the color from "gray" to "pure" while maintaining the same "brightness" and "hue". Using an appropriate combination of HLS, the operator can determine a desired color.

Fig. 34 shows the structure of a user interface for adjusting the image quality of a material. For each of the sliders shown in Fig. 34, an actual slider may be used, or they may be realized by displaying a simulated image on the computer screen. A combination of three sliders for hue, brightness and saturation is used to determine an object-specific color. Similarly, a combination of three sliders for red, green and blue is used to determine an object-specific color. The combination of the hue, brightness and saturation sliders is related to the combination of the red, green and blue sliders, so that when a slider of one of the combinations is moved, the slider of the other combination is also moved to match the movements between them. The operator selects a desired one of the two combinations to determine an object-specific color.

In this embodiment, an ambient light slider, a scattered light slider, a specular light slider, a metal image quality slider and a surface roughness slider are provided as sliders for determining the reflection attribute. Fig. 35 is a cross-sectional view of a color model. The colors on the cross-section all have the same saturation and contain an object-specific color. If the ambient light slider is moved, the color model is changed to the object-specific color. ence light is moved to change the brightness component of the object-specific color, the value of Ka changes continuously from the object-specific color to a black dot as shown by a bold line c. The scattered light slider is used to determine Kd by changing the brightness component of an object-specific light. The surface roughness slider is used to determine an area of a specular reflection component (see Fig. 32). The metal image quality slider is used to change the saturation component of an object-specific color as shown in Fig. 36, with the result being a continuous change from the object-specific color to the achromatic color (the color gray). When the metal image quality slider is moved to the metal side, the saturation component approaches the object-specific color, and when it is moved to the plastic side, the component approaches the achromatic color. As shown in Fig. 36, the reflected light slider determines the color Ks by changing the brightness component of the color determined by the metal image quality slider.

Fig. 37 shows the structure of another user interface which is different from that shown in Fig. 34. In this embodiment, the operator selectively determines a suitable object-specific color or a reflection attribute by means of menus displayed on the screen. In this embodiment, each parameter has a dispersion value, unlike the embodiment shown in Fig. 34 in which each parameter can be linearly determined. When the operator determines menus, the data on the object-specific color and the data on the reflection attribute corresponding to the determined menus are read from a storage device, so that the data specified under Calculate the units Ka, Kd and Ks described with reference to Fig. 30.

The user interfaces shown in Figs. 34 and 37 can be used in combination. For example, they can be designed so that the operator selects an object-specific color using the user interface shown in Fig. 34 and a reflection attribute using the user interface shown in Fig. 37, or vice versa. Moreover, they can be designed so that the user first roughly selects an object-specific color and a reflection attribute using menus and then finely adjusts them using the user interface shown in Fig. 34.

Next, a method for obtaining the image quality of a material of a typical object using the user interface shown in Fig. 34 will be described.

To express a luminous object, the luminous color of the object is first determined using either a combination of hue, brightness, and saturation sliders or a combination of red, green, and blue sliders. Next, the ambient light slider is set to a sufficiently large value. Such a sufficiently large ambient light component expresses the image of the material quality of the luminous object. The sliders for determining the reflection attribute (the scattered light, specular light, surface roughness, and metal image quality sliders) are set to arbitrary values as desired.

Similarly, when expressing an object with a matte color, such as plaster, the object-specific color is first determined. The specular light slider is set to the minimum value to display a glowing color. The diffused light slider is set to any value to adjust the brightness of an illuminated section. Then the ambient light slider is used to adjust the brightness of an unlit section.

To express a plastic object with a bright color, the object-specific color is first determined. The ambient light and scattered light sliders are adjusted in a similar manner to that of plaster, with the image quality slider of metal moved to the plastic side to set the color of the scattered light component to an achromatic color and the specular light slider set to an arbitrary value to thereby adjust the brightness of a portion with a bright color. In addition, the surface roughness slider is used to adjust the area of the portion with the bright color. Here, since Ks is set to an achromatic color, the specular reflection component has the same color as the light source regardless of the object-specific color.

Similarly, to express a metal object with a luminous color, the object-specific color is first determined. The scattered light slider is usually set to the minimum value to suppress the scattered light. The ambient light slider is set to an appropriate value taking the image effect into consideration. The metal image quality slider is moved to the metal side to adjust the specular light component to the object-specific color, and the specular light slider is set to an arbitrary value, thereby adjusting the brightness of the luminous part. color. In addition, the surface roughness slider is used to adjust the area of the portion with the glowing color. Since Ks is set to the object-specific color, the reflected light component will have the object-specific color when the object is illuminated by white light, for example.

In the above-described embodiment, the brightness component L in the HLS color model was changed to adjust the intensity of the ambient light component, the intensity of the scattered light component, and the intensity of the specular light component. The present invention is not limited to this, but any of the color model components can be changed if it changes the light intensity. For example, as shown in Fig. 35, the value on the line connecting the object-specific color and the point of the black color can be changed, resulting in an effect similar to that described above. Moreover, in the embodiments, the adjustment of the color of the specular reflection using the metal image quality slider was performed by changing the saturation component of the HLS color model. The present invention is not limited to such an embodiment, but any method can be used if interpolation between the achromatic color and an object-specific color can be performed. For example, as shown in Fig. 36, the value on the line connecting the object-specific color and the point of white color can be changed, resulting in an effect similar to that described above.

According to the invention, the movement path of an object is controlled using at least one of the magnitude and direction of a speed, the viewing direction of the object, and time. Therefore, the movement of an object can be determined intuitively.

Furthermore, the motion at the connection between key frames can be made smooth by setting the speed at the end point of one location to the same value as that at the start point of the next location.

In addition, an intermediate point specified on the path can be registered as a new key frame so that the path can be finely determined.

According to the invention, the color specific to an object is set independently of the reflection attribute, so that even a person without special technical knowledge can set the color easily, quickly and intuitively.

Claims (5)

1. Device for generating a movement path of an object, for example a camera, a light source or components, with: a motion path generator (203) that specifies start point information representing the motion start point (511) of a moving object and end point information representing a motion end point (521) of the moving object, and that generates, with reference to the specified start point information and the specified end point information, information representing a motion path from the motion start point to the motion end point of the object; a memory (205) storing, as the start point information for the movement start point and as the end point information for the movement end point, time information indicating a passage time of the moving object, position information indicating a passing position, speed vector information indicating a passing speed and a direction of the moving object, position of the determination information indicating whether a value of the position information has been explicitly designated, and speed vector determination information indicating whether a value of the speed vector information has been explicitly designated; and means for identifying whether the position information at the movement start point and the position information at the movement end point have been explicitly specified and whether the velocity vector information at the movement start point and the velocity vector information at the movement end point have been explicitly specified; wherein the path generator generates the motion path information according to the information stored in the memory and the motion path information as to whether the position information has been explicitly specified and whether the velocity vector information has been explicitly specified. 2. The apparatus according to claim 1, wherein the motion path generator stores the motion path information of the object as a polynomial with time variables, the degree of the polynomial being determined according to the amount of information according to the state of whether the position information has been explicitly specified and whether the velocity vector information has been explicitly specified, the coefficients of the polynomial being calculated so that the specified information is satisfied. 3. The apparatus of claim 1, comprising at least one display (101) that displays a motion path of an object, the displayed motion path being a line that indicates the motion path information determined by the motion path generator, a time lapse line that indicates a time lapse, a position symbol that represents position information at those positions for which position information has been specified, and a vector symbol that represents velocity vector information at the position for which the velocity vector information has been specified; and a time reference device that displays on the time sequence line a key frame symbol representing the designation of information at a position that indicates a time at which the position information was designated or at which the velocity vector information was designated. 4. The apparatus of claim 3, comprising an input device (103, 104) that performs a motion changing operation for the position symbol, the vector symbol and the key frame symbol, the input device changing information corresponding to the position symbol, the velocity vector symbol and the key frame symbol as inputted to cause the path generator to recalculate the motion path information. 5. The apparatus of claim 4, wherein the input device determines a position or a time on the motion path and determines a division of the motion path into two separate motion paths, wherein in accordance with the determined position or time, the motion path generator determines position and velocity vector information at the determined position or time from the motion path information to regenerate the position information according to the new start and end points of the two separate motion paths.